CN105092529A - Measurement device and method of medium refractive index - Google Patents

Abstract

The invention relates to a measurement device and method of a medium refractive index. The measurement device comprises a collimation light source, a first diaphragm, a second diaphragm, a round rotating stage, a stepper motor, a signal processor and a calibration light source, wherein the stepper motor is connected with the signal processor and the rotating stage; a jack post is arranged at the center of the rotating stage; a round objective table for holding a to-be-measured medium is arranged on the jack post; the to-be-measured medium is a wedge prism with measurable vertex angles; the side surface, at which one vertex angle side of the measureable vertex angles is located, is vertical to the horizontal plane on which the round objective table is located; the vertex angle side is parallel to the diameter of the round objective table; the circle center of the rotating stage and the circle center of the round objective table are located on the same vertical axis; a measurement arm is arranged on the rotating stage; a detector and a GaF2 lens are arranged on the measurement arm; the detector is connected with the signal processor; and a light emitting hole, a light passing hole of the first diaphragm, a light passing hole of the second diaphragm, the to-be-measured medium and a slit of the detector are located on the same horizontal axis. According to the measurement device and the measurement method, the refractive index of the medium can be measured with high accuracy.

Description

The measurement mechanism of medium refraction index and measuring method thereof

Technical field

The present invention relates to the fields of measurement of refractive index, particularly relate to a kind of measurement mechanism and measuring method thereof of medium refraction index.

Background technology

Refractive index, as one of important parameter in the fields such as Optical System Design, fiber optic materials development and gemstone testing, has important practical significance in field of measuring technique.Especially, in Optical System Design and fiber optic materials development field, the refractive index of accurate measuring media and optical fiber, the quality for Exact Design optical system and understanding fiber products is particularly important.

In refractometry field, more is adopt traditional critical angle method, the method for minimum deviation angle or interferometric method to measure.But, traditional refractive index measurement method still comes with some shortcomings part: such as, adopts the method for minimum deviation angle, if need the refractive index of high-acruracy survey sample, then need to utilize high process technology that sample is processed into triangle corner angle, add equipment cost undoubtedly; When critical angle method measures refractive index, then need the refractive index of testing sample must be less than the refractive index of standard model, to meet the condition of critical angle, and all band high index of refraction standard model material is rare and involve great expense, measurement range is severely limited, the precise decreasing especially when measuring solid dielectric.

Summary of the invention

Primary technical matters to be solved by this invention provides a kind of measurement mechanism that can carry out the medium refraction index of high-acruracy survey to the refractive index of medium for above-mentioned prior art.

Further technical matters to be solved by this invention provides a kind of measuring method utilizing the measurement mechanism measuring media refractive index of above-mentioned medium refraction index for above-mentioned prior art.

The present invention solves the technical scheme that above-mentioned primary technical matters adopts: the measurement mechanism of medium refraction index, it is characterized in that, comprise the collimated light source with light emission hole, first diaphragm, second diaphragm, circular universal stage, stepper motor, the visible laser source of signal processor and calibration, described universal stage connects stepper motor, stepper motor connection signal processor, the center of universal stage is provided with the jack-post perpendicular to surface level residing for universal stage, jack-post is provided with the circular stage placing testing medium, described testing medium is have the wedge prism that can survey drift angle, the described lateral vertical residing for a drift angle limit surveying drift angle is in the surface level residing for described circular stage, and the diameter of the parallel described circular stage in this drift angle limit, described circular stage is provided with the adjusting knob regulating circular stage oscilaltion, and described circular stage is parallel to surface level residing for universal stage, the center of circle of described universal stage and the center of circle of described circular stage are positioned on same vertical axis, described universal stage is also provided with length-adjustable gage beam, gage beam is provided with the detector obtaining intensity of illumination and the GaF converging light ₂lens, described detector is connected with signal processor, and the slit of the light hole of described light emission hole, the first diaphragm, the light hole of the second diaphragm, testing medium and detector is all on same level axis, described GaF ₂lens are between described testing medium and the slit of described detector, and the slit of described detector is positioned at GaF ₂one times of focal length place of lens.

Selectively, described detector is thermistor detector or infrared light-sensitive detector or photoelectron molded line formation detector or silicon photocell detector.

Selectively, described collimated light source is the narrow spaces light source of laser or Wavelength tunable.

Utilize a measuring method for above-mentioned measurement mechanism measuring media refractive index, it is characterized in that, in turn include the following steps:

(1) open collimated light source, adjustment gage beam and detector, make light emission hole, the light hole of the first diaphragm, the light hole of the second diaphragm, circular stage axis and detector slit be all on same level axis;

(2) drift angle of wedge shape testing medium is measured and by drift angle a drift angle limit residing for lateral vertical be placed on circular stage, and make the diameter of the parallel described circular stage in this drift angle limit, another lateral vertical residing for drift angle limit of adjustment drift angle incident ray out in light emission hole, reduce circular stage, make the upper surface of testing medium lower than the horizontal line determined by the first diaphragm, the second diaphragm;

(3) the direct impulse quantity of the signal processor real-time synchronization ground intensity of illumination data that send of pick-up probe and stepper motor, and store the direct impulse quantity of intensity of illumination data and stepper motor correspondingly; After stepper motor energising, the position marking current universal stage is φ at zero point ₀;

(4) oppositely regulate stepper motor, enabling signal processor and stepper motor, set the refracted ray angle of deviation Δ and initial zero φ estimated by signal processor ₀, the universal stage slow circumvolve that order is circular, and drive gage beam synchronous axial system by universal stage, wherein, the direct impulse quantity m received by described stepper motor and the rotation angle of deviation φ of universal stage _mbetween corresponding relation be:

Wherein, φ _mwhen representing that the direct impulse number that stepper motor receives is m, the deflection angle that universal stage correspondence turns over; When M represents that universal stage rotates 360 °, the umber of pulse required for stepper motor;

(5) the angle of deviation φ that universal stage rotates is treated _mreach the half estimating angle of deviation Δ, namely time, then circular stage rises, and makes universal stage rotate its angle of deviation φ by signal processor _mto estimating angle of deviation angle value Δ, i.e. φ _mduring=Δ, universal stage stops operating;

(6) signal processor is according to all intensity of illumination data stored in step (4) to step (5), obtains two numerical value E maximum in intensity of illumination data ₁, E ₂, and obtain respectively to should the direct impulse number m that receives of the stepper motor of two maximum intensity of illumination data simultaneously ₁, m ₂;

(7) the direct impulse number of calculated step motor is respectively m ₁, m ₂time, the deflection angle φ turned over corresponding to universal stage _m1, φ _m2: wherein,

(8) according to the drift angle of the testing medium obtained the deflection angle φ that universal stage correspondence turns over _m1, φ _m2, and angle corresponding relation, calculate the refractive index n of testing medium ₁:

(9) signal processor makes stepper motor rotate backward, and the reverse rotation of driven rotary platform, the intensity of illumination data again transmitted by signal processor real-time synchronization ground pick-up probe and the umber of pulse of stepper motor, and store the umber of pulse of intensity of illumination data and corresponding stepper motor one by one;

(10) when universal stage rotation increases to gradually to intensity of illumination time, then reduce stepper motor rotating speed, slow down the rotational speed of universal stage, and by signal processor record, all intensity of illumination data storing now correspondence and stepper motor direct impulse number;

When universal stage rotation is reduced to gradually to intensity of illumination time, then increase stepper motor rotating speed, accelerate the rotational speed of universal stage, by signal processor record, store now corresponding all intensity of illumination data and stepper motor direct impulse number;

(11) when universal stage rotation to stepper motor direct impulse number is during corresponding position, then circular stage declines, and makes testing medium depart from stop to light;

(12) when universal stage rotation increases to gradually to intensity of illumination time, then reduce stepper motor rotating speed, slow down the rotational speed of universal stage, and by signal processor record, all intensity of illumination data storing now correspondence and stepper motor direct impulse number;

When universal stage rotation is reduced to gradually to intensity of illumination time, then increase stepper motor rotating speed, accelerate the rotational speed of universal stage, make universal stage revolve turning to the null position in step (4), and by signal processor record, store all intensity of illumination data corresponding in this time period and stepper motor direct impulse number;

(13) signal processor is according to all intensity of illumination data stored in step (9) to step (12), obtains forward and backward two maximum numerical value E in intensity of illumination data successively ₃, E ₄, and obtain respectively to should the stepper motor direct impulse number m of two maximum intensity of illumination data simultaneously ₃, m ₄;

(14) the direct impulse number of calculated step motor is respectively m ₃, m ₄time, the deflection angle φ that universal stage correspondence turns over _m3, φ _m4:

(15) according to the drift angle of the testing medium obtained the deflection angle φ that universal stage correspondence turns over _m3, φ _m4, and angle corresponding relation, calculate the refractive index n of testing medium respectively ₂:

(16) step (4) is performed N time successively to the operation in step (15), obtain the refractive index value (n of 2N testing medium ₁, n ₂, n ₃, n ₄..., n _2N), and calculate the mean value of 2N testing medium refractive index respectively with variance δ:

$\stackrel{\‾}{n}=\frac{1}{2N}\underset{i=1}{\overset{i=2N}{\Σ}}{n}_i;$

$\mathrm{\δ}=\frac{1}{2N}\underset{i=1}{\overset{i=2N}{\Σ}}{(n_i-\stackrel{\‾}{n})}^2;$

Wherein, n _irepresent the refractive index value of i-th testing medium calculated;

(17) according to the mean value of the testing medium refractive index calculated in step (16) with variance δ, by the mean value of testing medium refractive index with variance δ sum or difference as the actual refractive index n of testing medium: wherein,

$n=\stackrel{\‾}{n}\±\mathrm{\δ}.$

Further, the measuring method of described measuring media refractive index also comprises exchanges different collimated light sources, and performs the step of operation in step (2) to step (17) successively.

Compared with prior art, the invention has the advantages that: in light emission hole, the light hole of the first diaphragm, the light hole of the second diaphragm, after the slit of testing medium and detector is all in same level axis, stepper motor driven rotary platform is utilized to rotate, signal processor rotates according to stepper motor received pulse number and universal stage the light intensity data that corresponding relation between angle of deviation and detector receive, synchronously, store stepper motor umber of pulse and intensity of illumination data correspondingly, and obtain two maximum intensity of illumination data by signal processor, then according to testing medium, angular relationship between circular stage, acquire the refractive index of testing medium first, then detector does reverse rotation with universal stage, and again obtains former and later two maximum intensity of illumination data by signal processor, and the refractive index of testing medium under again obtaining this state, circulate and so forth for several times, obtain the refractive index data of a series of testing medium, finally, utilize statistical method, obtain mean value and the variance of this serial refractive index data, thus accurately obtain the actual refractive index of testing medium.

Accompanying drawing explanation

Fig. 1 is the measurement mechanism structural representation of embodiment of the present invention medium refractive index;

Fig. 2 is the setting position schematic diagram of circular stage and testing medium in measurement mechanism shown in Fig. 1;

Fig. 3 is the schematic diagram of testing medium in Fig. 2;

Fig. 4 is the front schematic view of the first diaphragm in measurement mechanism shown in Fig. 1;

Fig. 5 is universal stage forward choosing when turning, the schematic diagram of incident ray after testing medium refraction;

Fig. 6 is that universal stage oppositely selects when turning, the schematic diagram of incident ray after testing medium refraction.

Embodiment

Below in conjunction with accompanying drawing embodiment, the present invention is described in further detail.

As shown in Figures 1 to 4, the measurement mechanism of embodiment of the present invention medium refractive index, the visible laser source 7 comprising collimated light source 1, first diaphragm 2, second diaphragm 3, circular universal stage 4, stepper motor 5, signal processor 6 and calibrate, collimated light source 1 has light emission hole 10, universal stage 4 connects stepper motor 5, stepper motor 5 connection signal processor 6, wherein, after the pulse that stepper motor 5 sends at Received signal strength processor 6, driven rotary platform 4 rotates, the center of universal stage 4 is provided with jack-post 40, this jack-post 40 is perpendicular to the surface level residing for universal stage 4, jack-post 40 is provided with circular stage 41, circular stage 41 is used for placing testing medium 8, wherein, this testing medium 8 is for having the wedge prism that can survey drift angle, and the drift angle surveyed of such as testing medium 8 is in Fig. 3 this can survey drift angle the side ABDE residing for a drift angle limit AB perpendicular to the surface level residing for circular stage 41, and this drift angle limit AB is parallel to the diameter GH of circular stage 41, now can ensure the diameter GH of limit DE by circular stage 41 side ABDE contacting circular stage 41, circular stage 41 is provided with the adjusting knob 410 regulating circular stage 41 oscilaltion, and circular stage 41 parallels with the surface level residing for universal stage 4, the center of circle of universal stage 4 and the center of circle of circular stage 41 are positioned on same vertical axis, during to ensure that circular stage 41 rotates with universal stage 4, both remain coaxial rotation, universal stage 4 is also provided with gage beam 42, the adjustable length of gage beam 42, measures to improve to greatest extent the resolution that universal stage 4 turns over angle, gage beam 42 is provided with detector 420 and GaF ₂lens 421, detector 420 connection signal processor 6, detector 420 in order to gather the intensity of illumination of the refracted ray irradiated in its surface, and sends signal processor 6 to, GaF ₂421, lens are used for, to after the refracted ray convergence of the dispersion after testing medium 8 refraction, making the light after convergence be radiated at the slit place of detector 420, simultaneously, the slit of the light hole of light emission hole 10, first diaphragm 2 of collimated light source 1, the light hole of the second diaphragm 3, testing medium 8 and detector 420 is all on same level axis, to ensure that measurement mechanism is under initial unmeasured state, incident ray is irradiated on testing medium 8 after can sequentially passing through the first diaphragm 2 and the second diaphragm 3, and is radiated on detector 420 after testing medium 8 reflects, wherein, GaF ₂lens 421 are between testing medium 8 and the slit of detector 420, and the slit of detector 420 is positioned at GaF ₂one times of focal length place of lens 421.Wherein, visible laser source 7 is for before mensuration work formally starts, whether the slit of the light hole of the light hole of the first diaphragm 2, the second diaphragm 3, testing medium 8 and detector 420 is all on same level axis and calibrates, to guarantee that incident ray can be radiated on testing medium 8 straight.According to measurement needs, detector 420 can choice for use thermistor detector or infrared light-sensitive detector or photoelectron molded line formation detector or silicon photocell detector.

In order to measure the refractive index situation of testing medium 8 pairs of different light rays, the collimated light source 1 in the present embodiment can select the narrow spaces light source of laser or Wavelength tunable.

Below in conjunction with Fig. 1 to Fig. 6, the measuring method utilizing measurement mechanism in the present embodiment to measure testing medium 8 refractive index is described.This measuring method in turn includes the following steps:

(1) open collimated light source 1, adjustment gage beam 42 and detector 420, make the light hole of the light hole of light emission hole 10, first diaphragm 2, the second diaphragm 3, the slit of circular stage 41 axis and detector 420 is all on same level axis;

(2) drift angle of wedge shape testing medium 8 is measured and by drift angle a drift angle limit AB residing for side ABDE be vertically placed on circular stage 41, and make the diameter GH of the parallel circular stage 41 of this drift angle limit AB, adjustment drift angle the side ADIC residing for the DF of another drift angle limit perpendicular to incident ray out in light emission hole 10, reduce circular stage 41, make the upper surface ABC of testing medium 8 lower than the horizontal line determined by the first diaphragm 2, second diaphragm 3;

(3) the direct impulse quantity of the signal processor 6 real-time synchronization ground intensity of illumination data that send of pick-up probe 420 and stepper motor 5, and store the direct impulse quantity of intensity of illumination data and stepper motor 5 correspondingly; After stepper motor 5 is energized, the position marking current universal stage 4 is φ at zero point ₀; Such as, when gage beam 42 turns to certain position with universal stage 4, then signal processor 6 records the intensity of illumination data that now detector 420 sends, and store the number of pulses that now receives of stepper motor 5 simultaneously, namely signal processor 6 stores the intensity of illumination data corresponding to each number of pulses;

(4) oppositely regulate stepper motor 5, enabling signal processor 6 and stepper motor 5, set the refracted ray angle of deviation Δ and initial zero φ estimated by signal processor 6 ₀, universal stage 4 slow circumvolve that order is circular, and drive gage beam 42 synchronous axial system by universal stage 4, wherein, the direct impulse quantity m received by the stepper motor 5 and rotation angle of deviation φ of universal stage 4 _mbetween corresponding relation be:

Wherein, φ _mwhen representing that the direct impulse number that stepper motor 5 receives is m, the deflection angle that universal stage 4 correspondence turns over; When M represents that universal stage 4 rotates 360 °, the umber of pulse required for stepper motor 5; Such as, when universal stage 4 rotates 360 °, stepper motor 5 needs umber of pulse to be 100, then the rotation angle of deviation φ of universal stage 4 under this condition _mand the corresponding relation between the direct impulse quantity m received by stepper motor 5 is as the direct impulse formula quantity m=2 that stepper motor 5 receives, then the now angle of deviation φ that turns over of universal stage 4 correspondence ₂=7.2 °.

(5) the angle of deviation φ that universal stage 4 rotates is treated _mreach the half estimating angle of deviation Δ, namely time, then circular stage 41 rises, and makes universal stage 4 rotate its angle of deviation φ by signal processor 6 _mto estimating angle of deviation angle value Δ, i.e. φ _mduring=Δ, universal stage 4 stops operating;

(6) signal processor 6 is according to all intensity of illumination data stored in step (4) to step (5), obtains two numerical value E maximum in intensity of illumination data ₁, E ₂, and obtain respectively to should the direct impulse number m that receives of the stepper motor 5 of two maximum intensity of illumination data simultaneously ₁, m ₂;

(7) the direct impulse number of calculated step motor 5 is respectively m ₁, m ₂time, the deflection angle φ turned over corresponding to universal stage 4 _m1, φ _m2: wherein,

(8) according to the drift angle of the testing medium 8 obtained the deflection angle φ that universal stage 4 correspondence turns over _m1, φ _m2, and angle corresponding relation, calculate the refractive index n of testing medium ₁:

Wherein, the angle corresponding relation in this step (8) is with reference to shown in figure 5:

The incident ray launched in light emission hole 10 enters in testing medium 8, and its incident angle is θ; When intensity of illumination data reach maximal value E ₁time, the angle of deviation that now universal stage 4 turns over is φ _m1; Along with on gage beam 42, detector 420 is rotated further by former direction, when intensity of illumination data reach second maximal value E ₂time, the angle of deviation that now universal stage 4 turns over is φ _m2.

Because incident ray is perpendicular to the side ADIC residing for the DF of drift angle limit, then incident ray vertical edges DF, so again because normal is perpendicular to limit DE, so γ+θ=90 °, then again because θ=θ ', therefore therefore, according in optics to the definition of medium refraction index, then this testing medium 8 is to the refractive index of this light

(9) signal processor 6 makes stepper motor 5 rotate backward, and driven rotary platform 4 reverse rotation, the intensity of illumination data again transmitted by signal processor 6 real-time synchronization ground pick-up probe 420 and the umber of pulse of stepper motor 5, and store the umber of pulse of intensity of illumination data and corresponding stepper motor one by one;

(10) increase to gradually when universal stage 4 rotates to intensity of illumination time, then reduce stepper motor 5 rotating speed, slow down the rotational speed of universal stage 4, and recorded, store all intensity of illumination data and the stepper motor direct impulse number of now correspondence by signal processor 6;

Be reduced to gradually when universal stage 4 rotates to intensity of illumination time, then increase stepper motor 5 rotating speed, accelerate the rotational speed of universal stage 4, recorded by signal processor 6, store now corresponding all intensity of illumination data and stepper motor direct impulse number;

(11) when universal stage 4 rotates to stepper motor 5 direct impulse number be during corresponding position, then circular stage 41 declines, and makes testing medium 8 depart from stop to light;

(12) increase to gradually when universal stage 4 rotates to intensity of illumination time, then reduce stepper motor 5 rotating speed, slow down the rotational speed of universal stage 4, and recorded, store all intensity of illumination data and the stepper motor direct impulse number of now correspondence by signal processor 6;

Be reduced to gradually when universal stage 4 rotates to intensity of illumination time, then increase stepper motor 5 rotating speed, accelerate the rotational speed of universal stage 4, make universal stage 4 revolve turning to the null position in step (4), namely now the angle of deviation of universal stage 4 returns to φ ₀, and recorded, store all intensity of illumination data and the stepper motor direct impulse number of correspondence in this time period by signal processor 6;

(13) signal processor 6 is according to all intensity of illumination data stored in step (9) to step (12), obtains forward and backward two maximum numerical value E in intensity of illumination data successively ₃, E ₄, and obtain respectively to should the stepper motor direct impulse number m of two maximum intensity of illumination data simultaneously ₃, m ₄;

(14) the direct impulse number of calculated step motor 5 is respectively m ₃, m ₄time, the deflection angle φ that universal stage 4 correspondence turns over _m3, φ _m4:

(15) according to the drift angle of the testing medium 8 obtained the deflection angle φ that universal stage 4 correspondence turns over _m3, φ _m4, and angle corresponding relation, calculate the refractive index n of testing medium 8 respectively ₂:

(16) step (4) is performed N time successively to the operation in step (15), obtain the refractive index value (n of 2N testing medium ₁, n ₂, n ₃, n ₄..., n _2N), and calculate the mean value of 2N testing medium refractive index respectively with variance δ:

$\stackrel{\‾}{n}=\frac{1}{2N}\underset{i=1}{\overset{i=2N}{\Σ}}{n}_i;$

$\mathrm{\δ}=\frac{1}{2N}\underset{i=1}{\overset{i=2N}{\Σ}}{(n_i-\stackrel{\‾}{n})}^2;$

Wherein, n _irepresent the refractive index value of i-th testing medium calculated;

(17) according to the mean value of the testing medium refractive index calculated in step (16) with variance δ, by the mean value of testing medium refractive index with variance δ sum or difference as the actual refractive index n of testing medium 8: wherein,

$n=\stackrel{\‾}{n}\±\mathrm{\δ}.$

It can thus be appreciated that the refractive index n of testing medium 8 exists numerical intervals within the scope of.

In addition, in order to the refractive index utilizing the measuring method in the present embodiment to measure testing medium 8 pairs of different light rays, as improvement, the measuring method of this medium refraction index also comprises exchanges different collimated light sources 1, and performs the step of operation in step (2) to step (17) successively.Change collimated light source 1 into required light source, this measuring method just can be utilized to measure the refractive index of testing medium 8 pairs of different light rays, expanded the usable range of measurement mechanism in the present embodiment.

Claims (5)

1. the measurement mechanism of medium refraction index, it is characterized in that, comprise the collimated light source with light emission hole, first diaphragm, second diaphragm, circular universal stage, stepper motor, the visible laser source of signal processor and calibration, described universal stage connects stepper motor, stepper motor connection signal processor, the center of universal stage is provided with the jack-post perpendicular to surface level residing for universal stage, jack-post is provided with the circular stage placing testing medium, described testing medium is have the wedge prism that can survey drift angle, the described lateral vertical residing for a drift angle limit surveying drift angle is in the surface level residing for described circular stage, and the diameter of the parallel described circular stage in this drift angle limit, described circular stage is provided with the adjusting knob regulating circular stage oscilaltion, and described circular stage is parallel to surface level residing for universal stage, the center of circle of described universal stage and the center of circle of described circular stage are positioned on same vertical axis, described universal stage is also provided with length-adjustable gage beam, gage beam is provided with the detector obtaining intensity of illumination and the GaF converging light ₂lens, described detector is connected with signal processor, and the slit of the light hole of described light emission hole, the first diaphragm, the light hole of the second diaphragm, testing medium and detector is all on same level axis, described GaF ₂lens are between described testing medium and the slit of described detector, and the slit of described detector is positioned at GaF ₂one times of focal length place of lens.

2. the measurement mechanism of medium refraction index according to claim 1, is characterized in that, described detector is thermistor detector or infrared light-sensitive detector or photoelectron molded line formation detector or silicon photocell detector.

3. the measurement mechanism of medium refraction index according to claim 1 and 2, is characterized in that, described collimated light source is the narrow spaces light source of laser or Wavelength tunable.

4. utilize a measuring method for measurement mechanism measuring media refractive index described in claim 1, it is characterized in that, in turn include the following steps:

(1) open collimated light source, adjustment gage beam and detector, make light emission hole, the light hole of the first diaphragm, the light hole of the second diaphragm, circular stage axis and detector slit be all on same level axis;

(2) drift angle of wedge shape testing medium is measured and by drift angle a drift angle limit residing for lateral vertical be placed on circular stage, and make the diameter of the parallel described circular stage in this drift angle limit, another lateral vertical residing for drift angle limit of adjustment drift angle incident ray out in light emission hole, reduce circular stage, make the upper surface of testing medium lower than the horizontal line determined by the first diaphragm, the second diaphragm;

(3) the direct impulse quantity of the signal processor real-time synchronization ground intensity of illumination data that send of pick-up probe and stepper motor, and store the direct impulse quantity of intensity of illumination data and stepper motor correspondingly; After stepper motor energising, mark current location is φ at zero point ₀;

(4) oppositely regulate stepper motor, enabling signal processor and stepper motor, set the refracted ray angle of deviation Δ and initial zero φ estimated by signal processor ₀, the universal stage slow circumvolve that order is circular, and drive gage beam synchronous axial system by universal stage, wherein, the direct impulse quantity m received by described stepper motor and the rotation angle of deviation φ of universal stage _mbetween corresponding relation be:

Wherein, φ _mwhen representing that the direct impulse number that stepper motor receives is m, the deflection angle that universal stage correspondence turns over; When M represents that universal stage rotates 360 °, the umber of pulse required for stepper motor;

(5) the angle of deviation φ that universal stage rotates is treated _mreach the half estimating angle of deviation Δ, namely time, then circular stage rises, and makes universal stage rotate its angle of deviation φ by signal processor _mto estimating angle of deviation angle value Δ, i.e. φ _mduring=Δ, universal stage stops operating;

(6) signal processor is according to all intensity of illumination data stored in step (4) to step (5), obtains two numerical value E maximum in intensity of illumination data ₁, E ₂, and obtain respectively to should the direct impulse number m that receives of the stepper motor of two maximum intensity of illumination data simultaneously ₁, m ₂;

(7) the direct impulse number of calculated step motor is respectively m ₁, m ₂time, the deflection angle φ turned over corresponding to universal stage _m1, φ _m2: wherein,

(8) according to the drift angle of the testing medium obtained the deflection angle φ that universal stage correspondence turns over _m1, φ _m2, and angle corresponding relation, calculate the refractive index n of testing medium ₁:

(9) signal processor makes stepper motor rotate backward, and the reverse rotation of driven rotary platform, the intensity of illumination data again transmitted by signal processor real-time synchronization ground pick-up probe and the umber of pulse of stepper motor, and store the umber of pulse of intensity of illumination data and corresponding stepper motor one by one;

(10) when universal stage rotation increases to gradually to intensity of illumination time, then reduce stepper motor rotating speed, slow down the rotational speed of universal stage, and by signal processor record, all intensity of illumination data storing now correspondence and stepper motor direct impulse number;

When universal stage rotation is reduced to gradually to intensity of illumination time, then increase stepper motor rotating speed, accelerate the rotational speed of universal stage, by signal processor record, store now corresponding all intensity of illumination data and stepper motor direct impulse number;

(11) when universal stage rotation to stepper motor direct impulse number is during corresponding position, then circular stage declines, and makes testing medium depart from stop to light;

(12) when universal stage rotation increases to gradually to intensity of illumination time, then reduce stepper motor rotating speed, slow down the rotational speed of universal stage, and by signal processor record, all intensity of illumination data storing now correspondence and stepper motor direct impulse number;

When universal stage rotation is reduced to gradually to intensity of illumination time, then increase stepper motor rotating speed, accelerate the rotational speed of universal stage, make universal stage revolve turning to the null position in step (4), and by signal processor record, store all intensity of illumination data corresponding in this time period and stepper motor direct impulse number;

(13) signal processor is according to all intensity of illumination data stored in step (9) to step (12), obtains forward and backward two maximum numerical value E in intensity of illumination data successively ₃, E ₄, and obtain respectively to should the stepper motor direct impulse number m of two maximum intensity of illumination data simultaneously ₃, m ₄;

(14) the direct impulse number of calculated step motor is respectively m ₃, m ₄time, the deflection angle φ that universal stage correspondence turns over _m3, φ _m4:

(15) according to the drift angle of the testing medium obtained the deflection angle φ that universal stage correspondence turns over _m3, φ _m4, and angle corresponding relation, calculate the refractive index n of testing medium respectively ₂:

(16) step (4) is performed N time successively to the operation in step (15), obtain the refractive index value (n of 2N testing medium ₁, n ₂, n ₃, n ₄..., n _2N), and calculate the mean value of 2N testing medium refractive index respectively with variance δ:

$\stackrel{\‾}{n}=\frac{1}{2N}\underset{i=1}{\overset{i=2N}{\Σ}}{n}_i;$

$\mathrm{\δ}=\frac{1}{2N}\underset{i=1}{\overset{i=2N}{\Σ}}{(n_i-\stackrel{\‾}{n})}^2;$

Wherein, n _irepresent the refractive index value of i-th testing medium calculated;

(17) according to the mean value of the testing medium refractive index calculated in step (16) with variance δ, by the mean value of testing medium refractive index with variance δ sum or difference as the actual refractive index n of testing medium: wherein,

$n=\stackrel{\‾}{n}+\mathrm{\δ}.$

5. the measuring method of measuring media refractive index according to claim 4, is characterized in that, also comprises and exchanges different collimated light sources, and performs the step of operation in step (2) to step (17) successively.